Patent GB-791977-A (GB)
Title: Preparation of alkaryl phosphoric acids
IPC: C07F9/12
Filed: 1956-01-19
Abstract: An alkaryl phosphoric acid is obtained by reacting together (a) 1 mol. of phosphorus pentoxide, (b) substantially 1 to 3 mols. of a hydroxyaromatic compound which is phenol, a -naphthol, b -naphthol, o-cresol, or catechol, and (c) substantially 1 to 3 mols, per mol, of aromatic hydroxy compound used, of an olefin having from 3 to 24 aliphatic carbon atoms and having the formula RR1=CH2, RR1C=CHR11, or RR1C=CR11R111, wherein R, R1, R11 and R111 are alkyl, aryl, or alkaryl radicals, at least one of the said radicals being alkyl or alkaryl, at a temperature of substantially 50-125 DEG  C. and for a period of time sufficient to form the alkaryl phosphoric acid.  When the reaction is complete the product may be topped at a somewhat higher temperature, e.g. about 150 DEG  C. or higher, under reduced pressure to remove any excess olefine and traces of unreacted hydroxyaromatic compound. The olefin and the hydroxyaromatic compound may first be mixed and the resulting mixture heated to a moderately elevated temperature, e.g. about 40 DEG  to 50 DEG  C., to form a homogeneous mixture and the phosphorus pentoxide then added gradually. Specified olefines of type (a) are 2,4,4-trimethyl-1-pentene, 2-ethyl-1-hexene, a -methyl-styrene, 2,3 - dimethyl - 1 - hexene, and 2 - methyl - 1 - pentadecene; of type (b): 2-methyl-2-butene, 2 - methyl - 2 - pentene, 3 - ethyl - 2 - pentene, 2,5 - dimethyl - 2 - hexene, 6 - butyl - 5 - undecene, 2 - methyl - 2 - tricosene, and 2,4,4 - trimethyl-2-pentene; and of type (c): 2,3-dimethyl-2-butene, 2,3-dimethyl-2-pentene, 3,4-dimethyl - 3 - hexene, and 2,3,4 - trimethyl - 2 - pentene.  Mixtures of olefines of these types are also suitable, e.g. diisobutylene.  It is desirable to use a slight excess of the olefin reactant based on the hydroxyaromatic compound although up to 2 or 3 mols. of olefin may be used for each mol. of hydroxyaromatic compound in which case a di- or tri-alkylated aromatic compound is obtained. The process may suitably be carried out by mixing the hydroxyaromatic compound and olefin, heating, e.g. to about 40-50 DEG  C. to obtain a homogeneous mixture and then bringing the temperature up to about 100 DEG  C. and adding the P2O5 reactant gradually, the reaction being continued at about 100 DEG  C. for a period of time, e.g. 5 to 10 hours after all the P2O5 has been added to ensure completion of the reaction.  Examples are given for the production of (1) and (2) octylphenyl phosphoric acids from various proportions of phenol, diisobutylene, and P2O5; (3) a mixture of mono- and di-butylphenyl phosphoric acids from phenol, isobutylene, and P2O5; (4) octyl-ortho cresyl phosphoric acids from ortho cresol, diisobutylene, and P2O5; (5) diphosphoric acids of octyl catechol from catechol, diisobutylene, and P2O5; (6) 2-ethylhexyl phenyl phosphoric acids from phenol, 2-ethyl-1-hexene, and P2O5; (7) nonyl phenyl phosphoric acids from phenol, propylene trimer, and P2O5; (8) octyl-beta-naphthyl phosphoric acids from beta-naphthol, diisobutylene, and P2O5, the reaction being carried out in the presence of toluene; and (9) phenylpropylphenyl phosphoric acids from phenol, a -methylstyrene and P2O5.  It is stated that with a 3:1 molar ratio of alkyl hydroxyaromatic compound to P2O5 the product comprises mainly mono- and di-esters of phosphoric acid with minor proportions of the pyrophosphoric acid ester but that the pyrophosphoric acid ester is probably the major component when a 2: 1 mol. ratio is employed.  The products are stated to be useful as additives for lubricants and as plasticisers, e.g. for coating compositions, and as wetting agents.